A Lumped-Circuit Model for a Triband Trapped Dipole Array-Part II: Stacked Arrays

Demands on emergency rf links have shown how important HF (330 MHz) communications can be for medium to long range. Efficient triband antennas have been developed and are quite popular for HF communications. In part 1, we described a lumped circuit model of the KLM 4-element KT-34A antenna. Here we consider its larger companion the 6-element KT-34XA and describe retuning the model for operation in the 10-, 15- and 20-m U.S. Army Military Affiliate Radio System (MARS) bands. We retune the parallel LC-circuits acting as traps and adjust the element lengths to obtain a MARSarray. A numerical model of this type of antenna is of interest to study antenna placement and the use of stacked arrays. We compare the radiation pattern of the 6-element KLM and MARS arrays and show examples for a stacked configuration over an imperfect ground plane. The model results for the individual arrays have the expected front and rear main beam angles but when stacked these angles change in a nonintuitive manner.